Drp1 Controls Complex II assembly and Fatty Acid Oxidation by Sdhaf2 Action on Mitochondria

The Dynamin-related GTPase, Drp1 (encoded by Dnm1l) plays a central role in mitochondrial fission and is requisite for numerous cellular processes however its role in oxidative metabolism remains unclear. Herein, we show that among human tissues, skeletal muscle exhibits the strongest correlations with the DNM1L gene. Knockdown of Drp1 (Drp1-KD) promoted mitochondrial hyperfusion in the muscle of male mice. Reduced fatty acid oxidation and accumulation of intramyocellular lipids along with increased muscle succinate was observed in Drp1-KD muscle. Muscle Drp1-KD reduced Complex II assembly and activity as a consequence of diminished mitochondrial translocation of succinate dehydrogenase assembly factor 2 (Sdhaf2). Restoration of Sdhaf2, normalized Complex II activity and lipid oxidation in Drp1-KD myocytes. Drp1 appears critical in maintaining mitochondrial Complex II assembly and fatty acid oxidation, suggesting a mechanistic link between mitochondrial morphology and skeletal muscle lipid metabolism which is of clinical significance in combatting metabolic diseases. Overall design: We generated a conventional muscle-specific Drp1 knockout heterzygous mice (Drp1-KD) and performed RNAseq in the quadricep muscle of the Control f/f and mDrp1HET mice.